Problem: Solve for $n$ : $2 + n = 1$
Subtract $2$ from both sides: $ \begin{eqnarray} \\ 2 + n &=& 1 \\ \\ {-2} && {-2} \end{eqnarray} $ $ \begin{eqnarray} \hphantom{2 + n} &\hphantom{=}& \hphantom{1} \\ n &=& 1 {- 2} \\ \end{eqnarray} $ Simplify. $ n = -1$